Differential actuator for prevention of misprinting in high speed mechanical calculators



1, 1957 B. H. TINGLEY ETAL 2,792,986

DIFFERENTIAL ACTUATOR FOR PREVENTION OF MISPRINTING IN HIGH SPEED MECHANICAL CALCULATORS Filed June 9, 1954 2 Sheets-Sheet l INVENTORJ BRUCE H. TINGLEY JOSEPH E. MAY BY ATTORNEY May 21, 1957 H. TINGLEY EI'AL 2,792,936

DIFFERENTIAL ACTUATOR FOR PREVENTION OF MISPRINTING IN HIGH, SPEED MECHANICAL CALCULATQRS Filed June 9, 1954 2 Sheets-Sheet 2 INVENTORS BRUCE H. TINGLEY JOSEPH E. MAY

ATTORNEY United States Patent ice DIFFERENTIAL ACTUATOR FOR PREVENTION OF MISPRINTING IN HIGH SPEED MECHANI- CAL CALCULATORS Bruce H. Tingley, West Norwalk, and Joseph E. May, Norwalk, Conn., assignors, by mesne assignments, to Sperry Rand Corporation, New York, N. Y., a corporation of Delaware Application June 9, 1954, Serial N 0. 435,516

Claims. (Cl. 235-60) This invention relates to new and useful improvements in calculating machines, and has particular reference to the prevention of misprinting when such machines are operated at high speeds.

In the operation of ten key key-set calculators of the motor driven type generally illustrated in U. S. Patent 2,229,980, issued January 28, 1941, the speed of operation has been limited to speeds in the neighborhood of 135 cycles per minute. It has been found that above this speed misprinting often ocurs especially of the higher numbers.

In machines of this type, stop pins are set by the operation of the keys and these determine the amount of linear movement of a series of slides which are adapted to move rearwardly until stopped by the set pin. With each slide is associated an adding rack which is spring coupled thereto. As each slide is allowed to move rearward, cooperating means on the rack and slide initially lock them together during the major portion of the rearward movement. The slides formerly were provided with rearwardly sloping tails which cooperated with a retract bar, cyclically operated, and, when operated at higher speeds than that mentioned above, the retract bar did not get out of the way of the slide tail, so as to permit the slide to swing up and lock with the rack as described in the above mentioned patent. As a consequence of this failure to lock the rack and slide together, the rack would overthrow and misprint. Hitherto this sloping tail had been used to cause the unlocking of the slide from the rack by the retract bar on the return movement of the bar.

The invention herein has been developed after considerable investigation of the reasons for the misoperation encountered. Briefly stated, the invention comprises the removal of the tail from the slide and the provision of cooperating means on the frame of the machine and the slide, which will unlock the slide from the rack on the return movement of the retract bar. In this manner, the retract bar as it is drawn back is not in the way of any tail to prevent the rack and the slide from immediately locking and yet on the return movement of the mechanism, the rack and the slide are unlocked at the proper moment. This means for unlocking the rack and slide also keeps the slide and the rack disengaged when they are in normal position of rest and until immediately after the slide starts to move rearwardly.

The present preferred form which the invention may assume is illustrated in the drawing, of which Fig. 1 is a side elevation showing the slide and the rack in their normal position of rest;

Fig. 2 shows the same parts in their relative position when the slide is stopped by a set pin;

Fig. 3 is a partial plan view of a series of slides and racks in their normal position of rest; and

Fig. 4 is a side elevation of a slide and rack as formerly employed showing them in normal as well as in locked relation.

2,792,986 Patented May 1,

Referring now merely to the specific form of the invention shown herein, reference is first directed to Fig. 4 which illustrates the former construction of the slide and the rack in operation. In this figure, which corresponds to Fig. 8 of the above mentioned patent, there is shown a series of stop pins 10, which are depressable by means of keys as shown in the patent. Associated with the pins 10 are differential members, such as the slide 11 and its related rack 12. The slide has on its front end a lip 13 adapted to abut a depressed pin 10 as the slide moves rearwardly. The slide has two spaced slots 14 and 15 in which ride headed rivets 16 and 17 fixed to the rack 12. The rack and the slide are connected by a yield spring 18 which permits a certain relative motion between them as set forth in the patent. An elongate slot 19 is cut in the slide to permit this connection, one end of the spring being connected to the slide and the other end to the rack. The front end of the slide has a de pendent finger 20 to which is attached a stronger spring 21 the other end of which is connected to a suitable fixed point on the machine frame.

The rear end of the slide has a sloping tapered tail '22 with which a retract bar 23 cooperates in the manner described in the patent. This end of the slide also has a raised projection forming a shoulder 24 which normally lies beneath a lug 25 fixed to the side of the rack 12. As the retract bar is moved to the right in Fig. 4 the spring 21 will move the slide rearwardly relatively to the rack until the left end of the slot 14 abuts the rivet 16, whereupon the spring will cause the slide to swing anti-clockwise to dispose the shoulder back of the lug as shown in dotted line in the figure. This action locks the rack and the slide so that when the lip of the slide encounters a depressed pin and stops, the rack will not overthrow. As has been previously stated, at high speeds the retract bar does not get out of the way of the tail of the slide quickly enough to let the slide and the rack lock together at the initial part of movement of the slide, and, therefore, the rack oftentimes overthrows and causes a mi-sprinting. On the return motion of the bar 23 the taper on the tail 22 permits the bar to depress the tail and thus unlock the slide from the rack and permit the slide to be moved to its normal position as shown in full lines in the figure.

In the improved form of the mechanism which constitutes the herein invention the tail of the slide has been cut 01f and now in the form of a rear edge the upper portion is substantially vertical, the lower portion of which is slightly curved as at 26, radius of this curve being less than the radius between the pivot point at rivet 16 and the upper portion of this rear edge of the slide. This presents a convex edge against which the bar 23 abuts and allows a free swinging of the slide around the rivet 16 as the retract bar is moved rearward. As shown by the reference characters practically all the other elements are the same as before, except that the slot 19 is now in the rack 12 since in this form the rack is in front of the slide. This permits the retract bar to get out of the way immediately and permit the locking action to take place as described. In this form of the invention the retract bar 23 has a series of rollers 27 rotatably mounted thereon, a roller for each slide 11. This construction re duces friction to a minimum for each slide thus further allowing an unhampered locking action.

The retract bar 23 at its ends slides in respective slots 28 in the inner vertical walls 29 and 30 of the machine frame. Each end of the bar 23 is pivotally connected to a. short link 31, the other end of which is pivotally connected to the lower end of an arm 32 rotatably mounted on a shaft 33 in the machine. On one of these arms 32 is a roller 34 riding in a curved cam groove 35 on a cam 36 which is oscillated by a shaft 37 in the manner shown in the patent or in any other suitable manner. Thus the retract bar is cyclically moved rearward and forward in the operation of the mechanism.

In the former mechanism shown in Fig. 4, the forward movement of the retract bar causedit to engage the tapered tail of the slide to unlock the slide from the rack. In the improved form, this action is achieved by placing a roller 38 over the upper edge 39 of each slide. These rollers are rotatably mounted on a rod 4%) which extends across between the walls 29 and30. The upper edge 39 of the slide has two levels connected by an intermediate sloping cam surface 41.' In the normal position of the slide with respect to the roller'38, as shown inPig. l, the upper level of the edge 39 contacts the roller and keeps the slide in position with the shoulder projection below the lug 25. However, shortly after the slide is released and starts to move rearwardly, the sloping cam surface 41 moves under the roller 38 and this permits the spring 21 to swing the slide up as before mentioned to lock the shoulder 24 back of the lug 25 in the manner described. Likewise, when the slide is moved back to normal position by the forward movement of the retract bar 23, the roller 38 will encounter the cam surface 41 and depress the slide and thereby lower the rear end of the slide to unlock the shoulder 24 from the lug 25. In the operation of this mechanism on a regular calculator, speeds as high as 200 cycles per minute have been obtained with perfect printing.

Briefly considered, the invention comprises the combination of a reciprocating rack, a difierential slide member connected to said rack for relative sliding and rocking motion, means on said slide and said rack for locking them together, means acting during the initial movement of said slide to cause first a sliding movement of the slide relative to said rack and then a rocking movement of said slide into locking engagement with said rack, and means cooperatively disposed on the slide and the frame of the machine to unlock the slide from the rack. on the return movement of the rack. The invention further includes a retract bar and the rear end of the slide so shaped as to permit rocking movement of the slide with a minimum of interference therewith by the bar at high speeds. While We have described what we consider to be a highly desirable embodiment of our invention, it is obvious that many changes in form could be made without departing from the spirit of our invention, and we, therefore, do not limit ourselves to the exact form herein shown and described, nor to anything less than the whole of our invention as hereinbefore set forth, and as hereinafter claimed.

What we claim as new, and desire to secure by Letters Patent, is

1. In a calculator having a reciprocatory rack, a slide having a lost motion connection with the rack and movable relatively thereto, reciprocatory means to move in one direction and release the slide and in another direction to return the slide to normal position, means engaging the slide to move it rearwardly when released and to rock it into locking engagement with the rack; the combination of means on the slide and means on the frame of the machine cooperating to unlock the slide from the rack as the slide is returned to normal position.

2. The invention of claim 1 further characterized in that the means on the frame of the machine is a roller and the means on the slide cooperating therewith is a cam surface sloping upwardly toward the rear of the slide.

3. The invention of claim 1 further characterized in that the means on the frame of the machine is a roller and the means on the slide cooperating therewith is a cam sloping upwardly toward the rear of the slide, the rear face of the slide being curve-d convexly toward the rear thereof to present such a surface in contact with the means returning it to normal position.

4. In a machine of the class described, a slide having a reciprocatory motion, a retract bar adapted to be moved to release said slide for motion in one direction and to return it in the other direction, means to move the slide in the first direction when released, a roller on the frame of the machine and engaging the upper edge ofthe slide, a sloping portion on the upper edge of the slide to pass under the roller in the initial portion of the rearward movement of the slide, and means to rock the slide as this surface passes under the roller, the rear'end of the slide being convexly curved relative to the retract bar to offer minimum interference to the rocking of the slide as the bar moves to release the slide.

5. In a machine of the class described, a reciprocatory rack having a locking element thereon, a slide associated with said rack, a yield spring connecting the slide and the rack providing for lost motion therebetween, a locking element on the slide to be associated with the locking element on the rack, a retract bar to hold the slide in a normal position of rest, means for retracting said bar to release said bar and for engaging said slide to return it to normal position of rest, a rivet on said rack riding in a slot in said slide and limiting the relative motion therebetWeen, a second spring connected at one end to the frame of the machine and at the other end to the slide below the longitudinal axis thereof and tending to rock said slide around said rivet to engage said locking elements, a roller on the frame of the machine abutting the upper edge of the slide, and a sloping surface on the upper edge of the slide and passing under said roller shortly after the slide starts to move rearwardly whereby the slide may then be rocked, the rear end of the slide presenting a convex surface to the retract bar to permit a minimum of interference by the retract bar to the rocking of the slide, the sloping surface passing under the roller on the return movement of the slide swinging the slide in the opposite direction to release said locking elements whereby the retract bar may return the slide to normal position against the resistance of the yield spring between the slide and the rack.

References Cited in the file of this patent UNITED STATES PATENTS 1,747,743 Sundstrand Feb. 18, 1930 1,784,862 Barrett Dec. 16, 1930 2,229,980 Landsiedel Jan. 28, 1941 2,695,134 Sundstrand Nov. 23, 1954 FOREIGN PATENTS 843,908 Germany July 14, 1952 

